Method for treating metal-contaminated water and soil
US7419605B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 19, 2006 |
| Grant date | Sep 2, 2008 |
| Priority date | — |
| Expiry date | Jan 19, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/914
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method for removing metal contaminants from water uses lignin derivatives, such as lignosulfonates and kraft lignin, a coagulant, such as a metal salt, and a pH-increasing composition. The lignin derivative is dispersed in the contaminated water, the coagulant is added and the pH is adjusted as required to cause flocculation. A sludge is formed that contains the metals and that is separated from the treated water by filtration. Related methods are used to reduce the leachable metal content of contaminated soils. The invention also provides a composition for stabilizing the metal contaminants in soil, comprising lignin derivatives, a coagulant and a composition for increasing the pH. The mixture is blended with the contaminated soil, reducing its leachable metal content.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.